Necrotizing Enterocolitis (NEC) is a form of ischemic bowel disease with unknown etiology which is usually diagnosed late in its clinical course. It affects mostly premature infants and delayed diagnosis is associated with worse outcome and death. The purpose of this study is to develop a non-invasive method for early detection of NEC in the premature infant. Based on earlier animal studies, the hypothesis is that CT scans of newborns' urine samples obtained after enteral administration of non-ionic iodinated contrast may be helpful in early detection of NEC by demonstrating urinary excretion of the contrast following systemic absorption from the diseased bowel. Status: Subject enrollment and data analysis completed.